you're lucky to have 90+ years old villagers. my oldest was 77 years. although they were all esteemed elders before they become 55 years old. they become elders from 21-55 years, especially the males because of the parenting skills trick that i use. but i have my game in slow mode because i don't want a very fast turnover of villagers, i want them to exist longer. maybe you have your game set in fast mode? i believe that's gonna make it harder for them to be esteemed elders. because they do less in more time. try setting your game in slow mode and maybe it's gonna make a difference.